2156921 has 8 divisors (see below), whose sum is σ = 2352000. Its totient is φ = 1966032.

The previous prime is 2156897. The next prime is 2156939. The reversal of 2156921 is 1296512.

2156921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 2156921 - 2⁶ = 2156857 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2156221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 80 + ... + 2078.

It is an arithmetic number, because the mean of its divisors is an integer number (294000).

2^2156921 is an apocalyptic number.

It is an amenable number.

2156921 is a deficient number, since it is larger than the sum of its proper divisors (195079).

2156921 is a wasteful number, since it uses less digits than its factorization.

2156921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2095.

The product of its digits is 1080, while the sum is 26.

The square root of 2156921 is about 1468.6459750396. The cubic root of 2156921 is about 129.2046308570.

The spelling of 2156921 in words is "two million, one hundred fifty-six thousand, nine hundred twenty-one".